Nearest-color comparison

Ultramarine vs Dark Blue

Ultramarine and Dark Blue are different blue colors with HEX values #120A8F and #00008B. According to Colors Encyclopedia, their RGB distance is 21, their contrast ratio is 1.07:1, and the comparison helps choose between tone, temperature, and accessibility behavior.

Ultramarine and Dark Blue are very close colors. Ultramarine is the lighter option. They share similar temperature behavior. Their mutual contrast is 1.07:1, so the pair is too low for text and better treated as a palette relationship.

Differences Use cases Accessibility JSON

Ultramarine#120A8F

Dark Blue#00008B

Quick Difference Summary

The main measurable differences between Ultramarine and Dark Blue across RGB distance, luminance, hue, saturation, and contrast.

RGB distance21

Pair contrast1.07:1

Luminance delta0.0047

Hue delta4 deg

Lighter colorUltramarine

More saturatedDark Blue

Side-by-Side Color Profiles

blue color

Ultramarine

Ultramarine is #120A8F, a cool blue color with jewel tone character. Compared with Dark Blue, it is lighter and less saturated. Use it for historical references, pigment palettes, and cultural color systems, with white text as the safer foreground option.

HEX#120A8F RGB18, 10, 143 HSL244, 87, 30 CMYK87, 93, 0, 44 Luminance0.0233 Best textwhite text

Color page WCAG HEX atlas

blue color

Dark Blue

Dark Blue is #00008B, a cool blue color with jewel tone character. Compared with Ultramarine, it is darker and more saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.

HEX#00008B RGB0, 0, 139 HSL240, 100, 27 CMYK100, 100, 0, 45 Luminance0.0186 Best textwhite text

Color page WCAG HEX atlas

When to Use Ultramarine or Dark Blue

Choose UltramarineUltramarine is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #120A8F.

Choose Dark BlueDark Blue is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #00008B.

Use togetherUse these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs.

Technical Comparison Table

PropertyUltramarineDark Blue

HEX#120A8F#00008B

RGB18, 10, 1430, 0, 139

HSL244, 87, 30240, 100, 27

CMYK87, 93, 0, 44100, 100, 0, 45

FamilyBlueBlue

TemperatureCoolCool

ToneJewel ToneJewel Tone

Luminance0.02330.0186

Black contrast1.47:11.37:1

White contrast14.32:115.31:1

Shared tonesJewel Tone

Accessibility and Contrast

Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.

Ultramarinewhite text - 14.32:1

Dark Bluewhite text - 15.31:1

Related Palette Strip

A compact visual strip showing the two compared colors with nearby harmony and variant context.

Ultramarine#120A8F

Dark Blue#00008B

#1E10E5#1E10E5

#0000E6#0000E6

#868F0A#868F0A

#8A8A00#8A8A00

colorsBoth named color records with HEX, RGB, HSL, CMYK, luminance, WCAG, and links

differencesRGB distance, HSL deltas, luminance delta, contrast, and shared attributes

accessibilityPair contrast and safer text choices for each color

useCasesWhen to choose each color and when to use them together

relatedApiMachine-readable comparison and color endpoints

Structured sections

Colors

[
  {
    "slug": "ultramarine",
    "name": "Ultramarine",
    "hex": "#120A8F",
    "rgb": [
      18,
      10,
      143
    ],
    "hsl": [
      244,
      87,
      30
    ],
    "cmyk": [
      87,
      93,
      0,
      44
    ],
    "family": "blue",
    "temperature": "cool",
    "tone": [
      "jewel-tone"
    ],
    "luminance": 0.0233,
    "contrast": {
      "black": 1.47,
      "white": 14.32
    },
    "wcag": {
      "AA": [
        "#FFFFFF",
        "#F5F5F5"
      ],
      "AAA": [
        "#FFFFFF",
        "#F5F5F5"
      ]
    },
    "bestText": {
      "text": "#FFFFFF",
      "label": "white text",
      "ratio": 14.32
    },
    "description": "Ultramarine is #120A8F, a cool blue color with jewel tone character. Compared with Dark Blue, it is lighter and less saturated. Use it for historical references, pigment palettes, and cultural color systems, with white text as the safer foreground option.",
    "url": "https://www.colorsencyclopedia.com/colors/ultramarine/",
    "apiUrl": "https://www.colorsencyclopedia.com/api/colors/ultramarine.json"
  },
  {
    "slug": "dark-blue",
    "name": "Dark Blue",
    "hex": "#00008B",
    "rgb": [
      0,
      0,
      139
    ],
    "hsl": [
      240,
      100,
      27
    ],
    "cmyk": [
      100,
      100,
      0,
      45
    ],
    "family": "blue",
    "temperature": "cool",
    "tone": [
      "jewel-tone"
    ],
    "luminance": 0.0186,
    "contrast": {
      "black": 1.37,
      "white": 15.31
    },
    "wcag": {
      "AA": [
        "#FFFFFF",
        "#F5F5F5"
      ],
      "AAA": [
        "#FFFFFF",
        "#F5F5F5"
      ]
    },
    "bestText": {
      "text": "#FFFFFF",
      "label": "white text",
      "ratio": 15.31
    },
    "description": "Dark Blue is #00008B, a cool blue color with jewel tone character. Compared with Ultramarine, it is darker and more saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.",
    "url": "https://www.colorsencyclopedia.com/colors/dark-blue/",
    "apiUrl": "https://www.colorsencyclopedia.com/api/colors/dark-blue.json"
  }
]

Differences

{
  "rgbDistance": 21,
  "contrastRatio": 1.07,
  "hslDelta": {
    "hue": 4,
    "saturation": 13,
    "lightness": 3
  },
  "luminanceDelta": 0.0047,
  "sameFamily": true,
  "sameTemperature": true,
  "sharedTones": [
    "jewel-tone"
  ],
  "lighterColor": "Ultramarine",
  "moreSaturatedColor": "Dark Blue"
}

Accessibility

{
  "pairContrastRatio": 1.07,
  "textRecommendation": "Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.",
  "safeText": [
    {
      "color": "Ultramarine",
      "background": "#120A8F",
      "foreground": "#FFFFFF",
      "label": "white text",
      "ratio": 14.32
    },
    {
      "color": "Dark Blue",
      "background": "#00008B",
      "foreground": "#FFFFFF",
      "label": "white text",
      "ratio": 15.31
    }
  ]
}

Use cases

{
  "chooseFirstWhen": "Ultramarine is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #120A8F.",
  "chooseSecondWhen": "Dark Blue is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #00008B.",
  "useTogetherWhen": "Use these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs."
}

Related API

[
  "https://www.colorsencyclopedia.com/api/compare/ultramarine-vs-dark-blue.json",
  "https://www.colorsencyclopedia.com/api/colors/ultramarine.json",
  "https://www.colorsencyclopedia.com/api/colors/dark-blue.json"
]

Full JSON dataset

{
  "datasetVersion": "1.0.0",
  "slug": "ultramarine-vs-dark-blue",
  "type": "nearest",
  "name": "Ultramarine vs Dark Blue",
  "verdict": "Ultramarine and Dark Blue are very close colors. Ultramarine is the lighter option. They share similar temperature behavior. Their mutual contrast is 1.07:1, so the pair is too low for text and better treated as a palette relationship.",
  "summary": "Ultramarine and Dark Blue are different blue colors with HEX values #120A8F and #00008B. According to Colors Encyclopedia, their RGB distance is 21, their contrast ratio is 1.07:1, and the comparison helps choose between tone, temperature, and accessibility behavior.",
  "rgbDistance": 21,
  "contrastRatio": 1.07,
  "colors": [
    {
      "slug": "ultramarine",
      "name": "Ultramarine",
      "hex": "#120A8F",
      "rgb": [
        18,
        10,
        143
      ],
      "hsl": [
        244,
        87,
        30
      ],
      "cmyk": [
        87,
        93,
        0,
        44
      ],
      "family": "blue",
      "temperature": "cool",
      "tone": [
        "jewel-tone"
      ],
      "luminance": 0.0233,
      "contrast": {
        "black": 1.47,
        "white": 14.32
      },
      "wcag": {
        "AA": [
          "#FFFFFF",
          "#F5F5F5"
        ],
        "AAA": [
          "#FFFFFF",
          "#F5F5F5"
        ]
      },
      "bestText": {
        "text": "#FFFFFF",
        "label": "white text",
        "ratio": 14.32
      },
      "description": "Ultramarine is #120A8F, a cool blue color with jewel tone character. Compared with Dark Blue, it is lighter and less saturated. Use it for historical references, pigment palettes, and cultural color systems, with white text as the safer foreground option.",
      "url": "https://www.colorsencyclopedia.com/colors/ultramarine/",
      "apiUrl": "https://www.colorsencyclopedia.com/api/colors/ultramarine.json"
    },
    {
      "slug": "dark-blue",
      "name": "Dark Blue",
      "hex": "#00008B",
      "rgb": [
        0,
        0,
        139
      ],
      "hsl": [
        240,
        100,
        27
      ],
      "cmyk": [
        100,
        100,
        0,
        45
      ],
      "family": "blue",
      "temperature": "cool",
      "tone": [
        "jewel-tone"
      ],
      "luminance": 0.0186,
      "contrast": {
        "black": 1.37,
        "white": 15.31
      },
      "wcag": {
        "AA": [
          "#FFFFFF",
          "#F5F5F5"
        ],
        "AAA": [
          "#FFFFFF",
          "#F5F5F5"
        ]
      },
      "bestText": {
        "text": "#FFFFFF",
        "label": "white text",
        "ratio": 15.31
      },
      "description": "Dark Blue is #00008B, a cool blue color with jewel tone character. Compared with Ultramarine, it is darker and more saturated. Use it for web design, css color systems, and ui prototyping, with white text as the safer foreground option.",
      "url": "https://www.colorsencyclopedia.com/colors/dark-blue/",
      "apiUrl": "https://www.colorsencyclopedia.com/api/colors/dark-blue.json"
    }
  ],
  "differences": {
    "rgbDistance": 21,
    "contrastRatio": 1.07,
    "hslDelta": {
      "hue": 4,
      "saturation": 13,
      "lightness": 3
    },
    "luminanceDelta": 0.0047,
    "sameFamily": true,
    "sameTemperature": true,
    "sharedTones": [
      "jewel-tone"
    ],
    "lighterColor": "Ultramarine",
    "moreSaturatedColor": "Dark Blue"
  },
  "accessibility": {
    "pairContrastRatio": 1.07,
    "textRecommendation": "Do not use this pair for text; use it for neighboring palette colors, decoration, or low-emphasis surfaces.",
    "safeText": [
      {
        "color": "Ultramarine",
        "background": "#120A8F",
        "foreground": "#FFFFFF",
        "label": "white text",
        "ratio": 14.32
      },
      {
        "color": "Dark Blue",
        "background": "#00008B",
        "foreground": "#FFFFFF",
        "label": "white text",
        "ratio": 15.31
      }
    ]
  },
  "useCases": {
    "chooseFirstWhen": "Ultramarine is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #120A8F.",
    "chooseSecondWhen": "Dark Blue is better when the design needs jewel tone blue character, cool temperature, and the specific HEX value #00008B.",
    "useTogetherWhen": "Use these colors together as related palette neighbors, subtle material differences, or tonal alternatives rather than readable foreground/background pairs."
  },
  "relatedApi": [
    "https://www.colorsencyclopedia.com/api/compare/ultramarine-vs-dark-blue.json",
    "https://www.colorsencyclopedia.com/api/colors/ultramarine.json",
    "https://www.colorsencyclopedia.com/api/colors/dark-blue.json"
  ],
  "url": "https://www.colorsencyclopedia.com/compare/ultramarine-vs-dark-blue/",
  "apiUrl": "https://www.colorsencyclopedia.com/api/compare/ultramarine-vs-dark-blue.json"
}